1. Field of the Invention
The present invention relates to a high-temperature regenerator of an absorption refrigerator, and more particularly, to the structure of a high-temperature regenerator that uses a surface combustion apparatus for the heating apparatus.
2. Background Art
An explanation of the general outline of an absorption refrigerator using a high-temperature regenerator of the prior art is given in FIG. 3.
In the drawing, reference numeral 1 is an evaporator/absorber drum (a lower drum). An evaporator 2 and an absorber 3 are housed in this evaporator/absorber drum 1. Reference numeral 4 is the high-temperature regenerator as claimed in this embodiment, which is equipped with a burner 5. An absorption fluid pump P, a low-temperature heat exchanger 7 and a high-temperature heat exchanger 8 are provided intermediately in diluted absorption fluid piping 6 extending from the absorber 3 to the high-temperature regenerator 4.
Reference numeral 10 is a high-temperature drum (an upper drum), and a low-temperature regenerator 11 and a condenser 12 are housed within this high-temperature drum 10. Reference numeral 13 is a refrigerant vapor pipe extending from the high-temperature regenerator 4 to the low-temperature regenerator 11, reference numeral 16 is a refrigerant fluid flow down pipe extending from the condenser 12 to the evaporator 2, reference numeral 17 is a refrigerant circulating pipe connected to the evaporator 2, and reference numeral 18 is a refrigerant pump. Reference numeral 21 is a cold water pipe connected to the evaporator 2.
Reference numeral 22 is an intermediate absorption fluid pipe extending from the high-temperature regenerator 4 to the high-temperature heat exchanger 8, and reference numeral 23 is an intermediate absorption fluid pipe extending from the high-temperature heat exchanger 8 to the low-temperature regenerator 11. Reference numeral 25 is a condensed absorption fluid pipe extending from the low-temperature regenerator 11 to the low-temperature heat exchanger 7, and reference numeral 26 is a condensed absorption fluid pipe extending from the low-temperature heat exchanger 7 to the condenser 3. In addition, reference numeral 29 is a cooling water pipe.
During operation of the absorption refrigerator composed in the manner described above, the burner 5 of the high-temperature regenerator 4 burns causing dilute absorption fluid such as an aqueous lithium bromide solution (LiBr) (containing a surface active agent), which has flowed in from absorber 3, to be heated and boil resulting in separation of refrigerant vapor from the dilute absorption fluid. The dilute absorption fluid is concentrated as a result of this operation.
The refrigerant vapor flows to the low-temperature regenerator 11 through the refrigerant vapor pipe 13. Intermediate absorption fluid from the high-temperature regenerator 4 is heated in the low-temperature regenerator 11, and the condensed refrigerant fluid flows to the condenser 12. In the condenser 12, the refrigerant vapor that has flowed in from the low-temperature regenerator 11 condenses and flows down to the evaporator 2 with the refrigerant fluid that has flowed in from the low-temperature regenerator 11.
In the evaporator 2, the refrigerant fluid is disseminated due to the operation of the refrigerant pump 18. Cold water, the temperature of which has been lowered as a result of cooling by this dissemination, is supplied to the load. The refrigerant vapor that has vaporized in the evaporator 2 flows to the absorber 3 where it is absorbed by the above-mentioned disseminated absorption fluid.
On the other hand, the intermediate absorption fluid, the concentration of which has increased following separation of the refrigerant vapor in the high-temperature regenerator 4, flows to the low-temperature regenerator 11 after passing through the intermediate absorption fluid pipe 22, the high-temperature heat exchanger 8 and the intermediate absorption fluid pipe 23.
The intermediate absorption fluid is heated by a heater 14 through which the refrigerant vapor from the high-temperature regenerator 4 flows. The concentration of the absorption fluid is further increased following separation of the refrigerant vapor from said intermediate absorption fluid.
Concentrated absorption fluid that has been heated and concentrated in the low-temperature regenerator 11 flows into the condensed absorption fluid pipe 25 and then flows to the absorber 3 after passing through the low-temperature heat exchanger 7 and the condensed absorption fluid pipe 26 followed by dripping onto the cooling water pipe 29 from a dissemination apparatus 30. The concentration of the refrigerant increases as a result of absorbing refrigerant vapor to be described later that enters through the evaporator 2. The absorption fluid having an increased refrigerant concentration is preheated in the low-temperature heat exchanger 7 and the high-temperature heat exchanger 8, and flows into the high-temperature regenerator 4 due to the driving force of the absorption fluid pump P.
Next, the following provides an explanation of the high-temperature regenerator 4.
As shown in FIG. 3, fuel 31, which is taken in towards the burner 5 of the high-temperature regenerator 4, and air, which is sent from a blower 33, are mixed and ignited to start combustion.
At this time, as shown in FIGS. 4A and 4B, air and fuel are mixed in an air-fuel mixture chamber 35 to form an air-fuel mixture. A surface combustion plate 37 is provided on the downstream side of the air-fuel mixture chamber 35. A large number of combustion holes through which the air-fuel mixture passes are provided in the surface combustion plate 37. An ignition device that ignites the air-fuel mixture and various types of sensors (not shown) that detect the combustion flame produced by ignition are provided in the vicinity of the surface combustion plate 37.
The air-fuel mixture chamber 35 and a combustion chamber 39 are connected with the surface combustion plate 37 in between. The periphery of the combustion chamber 39 is surrounded by pipe wall 41. Fluid pipe group 43 is continuous with the pipe wall 41, and absorption fluid flows through the inside of said fluid pipe group 43 in the form of convection flow.
In the case the surface area of a fire hole 45 formed by the boundary between the air-fuel mixture chamber 35 and the combustion chamber 39 is formed to be smaller than the longitudinal cross-sectional surface area of the air-fuel mixture chamber 35 and the combustion chamber 39 parallel to the surface combustion plate (see FIGS. 4A and 4B), it is necessary to cover the sites inside the chamber around the fire hole 45 with a refractory material 46 to protect the area around the fire hole 45 from the effects of the heat inside the chamber.
However, since it is necessary for the refractory material 46 which covers the fire hole 45 to be of a suitable thickness (for example, about 50 mm), it inhibits the transfer of heat to the pipe wall 41. Moreover, there is also the problem of increased NOx values due to the refractory material 46 reaching high temperatures.
In order to solve the above-mentioned problems, the object of the present invention is to provide a high-temperature regenerator that is able to avoid the problem of increased NOx values without inhibiting heat transfer.